1. Field of the Invention
The present invention relates in general to piezoelectric transducers for converting mechanical energy into electrical energy, and more specifically relates to transducers that are formed from a compliant polymeric piezoelectric material.
2. Description of the Prior Art
Devices are known in the art that employ piezoelectric crystals mounted in cantilever fashion and end loaded such that they are caused to oscillate during movement of the devices as shown in U.S. Pat. to Ko, No. 3,456,134. The Ko patent employs an oscillating piezoelectric crystal that converts mechanical energy into electrical energy to power human implants such as heart pacemakers. Used solely as an energy transducer the Ko device may operate relatively satisfactorily, but for other uses such as a motion detector it has several deficiencies. Firstly, because the Ko device employs a crystal as its piezoelectric sensing medium, its sensitivity is limited by the rigidity of the crystal; secondly, the Ko device is not adapted to provide a uniform output upon movement of the device in various directions and in fact will provide substantially no output in certain directions.
The energy transducer of the present invention employs a resilient polymeric piezoelectric material that not only provides high sensitivity, but also is relatively inexpensively and readily manufactured.